POLYMERS　Vol.67　No.4
>> Japanese >> English
COVER STORY
Shining Polymers Structured at the Surface and Interface
COVER STORY: Highlight Reviews
Actions of Molecules at Interfaces—Alignment and Flow Takahiro SEKI
<Abstract> Molecular behavior at interfaces provides various significant issues in polymer science and technologies. Continuous efforts are made toward precise understandings of the interfacial phenomena and creations of new functions based on such unique molecular behavior at interfaces. This short review article introduces several new trends focusing on the molecular alignment and molecular flow at and near interfaces. Surface alignment of liquid crystal (LC) materials is essential in the LC display panel fabrication, however, new surface alignment methods are still emerging. Examples can be found in LC alignment switching by a redox active polymer surface, and successful LC photoalignment from the free surface in side chain LC polymer films. In the nanoimprint process, monomer materials flow at a nanometer-scale space. A recent study has revealed a distinctive flow behavior that cannot be explained by the observed viscosity of the bulk state in such restricted space.
Keywords: Interfaces / Command Surface / Liquid Crystals / Surface Segregation / Free Surface / Nanoimprint
Top of the Page▲
Control of Surface Wettability Using Polymer Brushes and A New Approach to Their Large Area Fabrication Tomoya SATO, Chihiro URATA, Atsushi HOZUMI
<Abstract> Polymer brushes have attracted much attention due to their unique surface functionalities. In this article, we report on the control of surface wettability using a variety of polymer brushes and their practical applications. We also introduce an easy and inexpensive method named “Paint-on”, which enables the large-area fabrication of polymer brushes in air without the need for any specific equipment, and careful control of process parameters.
Keywords: Polymer Brushes / Wettability / Oil / Water Separation / Paint-on Method / Large Area Fabrication / Sol-Gel
Top of the Page▲
CO2 Separation by Polymer Membranes Containing Nanoparticles with Gas Permeable Nano-Space Hiroyoshi KAWAKAMI
<Abstract> Carbon dioxide (CO2) separation or capture from flue gasses is of particular importance in reducing greenhouse gas emissions and in preserving environmental health. At least approximately 20% of CO2 reduction by 2050 is desirable to be achieved by applying CCS (carbon dioxide capture and storage) to the large point sources. In this article, we report the CO2 separation by polymer membranes containing nanoparticles with gas permeable nano-space. The formation of gas transport channels by a channel-like assembly of the nanoparticles showed the dependency of the nanoparticle concentration and the CO2 permeability of the membrane significantly increased with an increase of the concentration without the decreasing CO2/N2 selectivity. The syntheses of the nanoparticles are cost-effective, and the nanoparticles with controllable nano-space can be easily synthesized by selection of the appropriate building blocks. Hence, the membranes composed of the nanoparticles having gas permeable nano-space have excellent potential for large-scale high-performance CO2 separation membranes.
Keywords: Carbon Dioxide / Gas Separation / Silica Nanoparticle / Gas Permeable Nano-Space / Maxwell Model / Carbon Dioxide Capture and Storage / Mixed Matrix Membraneis
Top of the Page▲
COVER STORY: Topics and Products
A New Strategy for Developing Microscopic Wrinkled Surfaces by Using Chitosan Hironori IZAWA, Hiroyuki SAIMOTO
<Abstract> We accidentally found a phenomenon forming micro-scale wrinkles on a chitosan film by immersing it in a phenolic acid solution, followed by horseradish peroxidase-catalyzed surface reaction and drying. We revealed that the skin layer, composed of ionic bonding between chitosan and an oligophenolic residue formed by the horseradish peroxidase-catalyzed surface reaction, induced surface wrinkling. Furthermore, we developed a novel surface wrinkling system inspired by this knowledge in which a skin layer formed by ionic crosslinking of chitosan and alginate induced surface wrinkling. This knowledge would provide a new strategy for developing surface wrinkling.
Keywords: Chitosan / Surface Wrinkling / Horseradish Peroxidase / Skin Layer / Bio-Based Materials / Biomimetic Materials
Top of the Page▲
Construction of Polymer Interface Connecting Biomolecule with an Electrochemical Sensor Taira KAJISA
<Abstract> In order to develop electrochemical biosensors, it is important to construct an interfacial material on electrodes for a selective and highly sensitive detection of biomarkers, since the occurred charge changes in target molecules is cancelled by the ions and contaminants of biofluids. In this chapter, we introduce two examples of biosensing using polymer modified electrodes. Firstly, a selective and highly sensitive biosensor was investigated using the molecularly imprinted polymer (MIP)-coated gate field-effect transistor (FET). Dopamine-imprinted MIP-FET detected dopamine selectively from the other catecholamines. Secondly, cell sensing was achieved by a potentiometer for polycatecholamine coated-Au electrode. A nano-layer of a polycatecholamine electrode showed pH sensitivity without response to the other ions. Cells were cultivated on the electrode and we monitored the increase of surface potential as a respiratory activity during proliferation of the cells. In conclusion, uniform and thickness controlled polymer interfaces at the electrode make it possible for electrochemical biosensor to detect the biomolecular charge events with selective and high sensitivity.
Keywords: Biosensor / Biomimetic / Molecularly Imprinted Polymer / Field-Effect Transistor / Impedance / Potentiometer / Polycatecholamine / Cell Sensing
Top of the Page▲
Polymer Wire Architect of Artificial Neural Networks Megumi AKAI-KASAYA
<Abstract> Artificial intelligence (AI) consisting of deep-layered neural networks (NNs) is an incredibly exciting and powerful intelligent artifact, and is used to solve many real-world problems. The NN hardware having cognitive and learning abilities is now actively developed by using analog non-volatile memory devices. We perform a prototype construction of molecular NNs consisting of conducting polymer PEDOT:PSS. The PEDOT wire grows dendritically, and bridges between electrodes immersed in the monomer solution, which forms highly-controllable memristive wires. Typical conductance values between the electrodes were increased by 1 to 2 orders of magnitude when the PEDOT:PSS wires were fully grown between the electrodes. By using external learning controllers and in-situ conductance readout circuits, PEDOT wires can selectively be grown between appropriate electrodes. We demonstrated that the molecular neural network consisting of PEDOT:PSS wires acquired linearly-separable Boolean logical functions and auto-encoder, through the supervised and un-supervised learnings, respectively. These results may expand variety of present neuromorphic computing architectures designed mainly for solid-state CMOS devices.
Keywords: Neural Network / Polymer Wire / Conducting Polymer / Artificial Intelligence / Machine Learning
Top of the Page▲
Polymer Science and I: A Personal Account
Toward a Ground One Cannot Break Without a Polymeric Catalyst Yukihiro ARAKAWA
<Abstract> My research life cannot be highlighted without polymeric catalysts for organic synthesis. Some unique catalyses as well as synthetic applications that are difficult to achieve by similar monomeric catalysts have been found through my PhD, postdoc, and current studies, which are recorded in this essay with my trivial experiences.
Top of the Page▲
Front-Line Polymer Science
Recent Developments in Structure and Properties of Block Copolymer Materials Shinichi SAKURAI
<Abstract> In this article, I review recent developments in structure and properties of block copolymer materials in terms of the following aspects: (1) Mechanical properties of sphere-forming block copolymers, and (2) optical properties of cylinder-forming block copolymers.
Keywords: Block Copolymer / Mechanical Properties / Optical Properties / Thermoplastic Elastomer / Form Birefringence / Small-Angle X-Ray Scattering / Polarizing Optical Microscope
Top of the Page▲
 
Copyright(C) 2018 The Society of Polymer Science, Japan All Rights Reserved.